DIY Electric Grill Powered by ESPHome

Tags: #<Tag:0x00007f326978bea8>

After 1.5 years of procrastination I finally have a working implementation of an electric grill/smoker powered by ESPHome!

It all began when I saw the Alton Brown DIY flower pot smoker. Something like this:

I then saw the Weber Smokey Joe converted to a smoker with a tamale pot and I knew this is what I wanted.


But I haven’t seen anyone build this as an electric smoker so I decided that I would be the first.

I disassembled the counter-top burner and mounted the heating element to the charcoal grate, for the past year and a half I was using the smoker like this with the base of the electric burner outside of the grill. The temp control was terrible. The temp control seems to use a knob with a bi-metallic element that turns the grill on and off, and by removing the heating element the temp control got much worse.

I decided that it needed PID but I also wanted it integrated into Home Assistant. I went to the esphome webpage and found that there was no PID climate. I decided to start writing a custom climate implementation with PID but my c++ skills are not the best. This was during my last semester of my engineering degree so it got pushed to the back burner.

Every few months I would search to see if someone would beat me to making the PID climate and a few months ago it finally happened and made its way into the esphome beta build. My work got in the way of starting the implementation and soon enough, PID climate was pulled into the stable release. I was going to design a PCB but I got impatient so I used a ESP32 devkit C board and made this spaghetti monstrosity with all black wire that will soon be wrapped in electrical tape and hidden from the world.

After about a day of tuning IT WORKS! The system response could be a little better but I’m pretty happy. It will most likely also need two tuning profiles for grill an smoker mode.


This is the controller all closed up.



From left to right we have power in, power out, and the 4 temperature probes.

Where the burner coil is located.

For the grill temperature probe I use a Thermoworks High Temp Air Probe. Wood chips sit in a stainless pie pan on top of the burner coil.

Wiring and mounting of burner. Mounting uses no hardware. The metal bracket shown came as part of the coil, i ground it down so it would fit between the charcoal grate.

Smoker mode!

This schematic was originally going to turn in to a PCB with the ESP32 WROOM module soldered directly but I did not want to wait. All wiring is pretty much the same. The pins labeled Jack1-4 are for the switched 1/8 jacks to detect if a probe is connected. The same can be implemented in software since the voltage at the ADC will be 3.3V without a probe plugged in. I am also not using the exact SSR from the schematic, that was going to be PCB mounted but instead I used a common Fotek SSR.

esphome:
  name: lil_smokey
  platform: ESP32
  board: nodemcu-32s
  on_boot:
    then:
      - sensor.rotary_encoder.set_value:
          id: rotary
          value: 1    
      - switch.turn_on: ntc_vcc


wifi:
  ssid: "nice try"
  password: "wouldnt you like to know"
    # Optional manual IP
  manual_ip:
    static_ip: nope
    gateway: no way
    subnet: kick rocks
  # Enable fallback hotspot (captive portal) in case wifi connection fails
  ap:
    ssid: "Lil Smokey Fallback Hotspot"
    password: "nuh uh"

captive_portal:

# Enable logging
logger:


# Enable Home Assistant API
api:

ota:

### Pull time from Home Assistant because everything needs a clock on it ###
time:
  - platform: homeassistant
    id: my_time

### Setup i2c for display and ADC ###
i2c:
  sda: GPIO15
  scl: GPIO4

switch:
### Power for Thermistors ###
  - platform: gpio
    pin: GPIO19
    id: ntc_vcc
### Switches for Setting and Getting PID Values in Home Assistant ###   
  - platform: template
    name: "PID Set"
    turn_on_action:
      - climate.pid.set_control_parameters:
          id: pid_climate
          kp: !lambda
              return id(p_coefficient).state;
          ki: !lambda
              return id(i_coefficient).state;
          kd: !lambda
              return id(d_coefficient).state;
  - platform: template
    name: "Get PID Values"
    turn_on_action:
      - homeassistant.service:
          service: input_number.set_value
          data:
            entity_id: input_number.p_coefficient
            value: !lambda return id(kp).state;
      - homeassistant.service:
          service: input_number.set_value
          data:
            entity_id: input_number.i_coefficient
            value: !lambda return id(ki).state;
      - homeassistant.service:
          service: input_number.set_value
          data:
            entity_id: input_number.d_coefficient
            value: !lambda return id(kd).state;
### Switch to reset integral term for PID calculation ###
  - platform: template
    name: "Reset Integral"
    turn_on_action:
      - climate.pid.reset_integral_term: pid_climate
      
### Rotary Encoder Button - Some code to function as state machine - UNDER CONSTRUCTION ###
binary_sensor:
  - platform: gpio
    pin: GPIO21
    id: encoder_button
    filters:
      - invert:
    on_press:
      then:
        - if:
            condition:
               lambda: 'return id(edit);'
            then:
              - globals.set:
                  id: edit
                  value: "false"
              - sensor.rotary_encoder.set_value:
                  id: rotary
                  value: !lambda |-
                    return id(current_page);
            else:
              - globals.set:
                  id: edit
                  value: "true"
              - sensor.rotary_encoder.set_value:
                  id: rotary
                  value: 0
              - display.page.show: !lambda |-
                  if (id(current_page)==1) {
                    return id(page11);
                  } if (id(current_page)==2) {
                    return id(page12);
                  } if (id(current_page)==3) {
                    return id(page13);
                  } if (id(current_page)==4) {
                    return id(page14);
                  } if (id(current_page)==5) {
                    return id(page15);
                  }

### Global Vars for OLED Menu State Retention ###
globals:
  - id: edit
    type: bool
    initial_value: "false"
  - id: current_page
    type: int
    initial_value: "1"

### PID Loop ###
climate:
  - platform: pid
    visual:
      min_temperature: 150 °F
      max_temperature: 525 °F
      temperature_step: 1 °C  
    id: pid_climate
    name: "Electric Grill"
    sensor: temp1
    default_target_temperature: 0°C
    heat_output: heater
    control_parameters:
      kp: 0.037
      ki: 0.0003
      kd: 3
      min_integral: 0
      max_integral: 0.9

### Slow PWM for PID Output ###
output:
  - platform: slow_pwm
    pin: GPIO12
    id: heater
    period: 3s

### External Analog to Digital Converter Setup ###
ads1115:
  - address: 0x48
  
sensor:
### Sensors to Read PID information into Home Assistant ###
  - platform: pid
    name: "PID Result"
    type: RESULT
  - platform: pid
    name: "PID Integral Term"
    type: INTEGRAL
  - platform: pid
    name: "PID Derivative Term"
    type: DERIVATIVE
  - platform: pid
    name: "PID Proportional"
    type: PROPORTIONAL
  - platform: pid
    name: "PID P Coefficient"
    id: kp
    type: KP
  - platform: pid
    name: "PID I Coefficient"
    id: ki
    type: KI
  - platform: pid
    name: "PID D Coefficient"
    id: kd
    type: KD
  - platform: pid
    name: "PID Output"
    type: HEAT
### Sensors to read input numbers for PID tuning in Home Assistant ###
  - platform: homeassistant
    name: "P Coefficient"
    entity_id: input_number.p_coefficient
    id: p_coefficient
  - platform: homeassistant
    name: "I Coefficient"
    entity_id: input_number.i_coefficient
    id: i_coefficient
  - platform: homeassistant
    name: "D Coefficient"
    entity_id: input_number.d_coefficient
    id: d_coefficient
###-----------------------------------------------------------------------------------------------------###
###                                     Temperature Sensing                                            ###
###-----------------------------------------------------------------------------------------------------###
  - platform: ntc
    sensor: resistance_sensor
    id: temp1
    name: "temp1"
    calibration:
      b_constant: 3950
      reference_temperature: 25°C
      reference_resistance: 100kOhm
### Exponential filter to smooth temp readings to mitigate derivative term instability ###
    filters:
      - exponential_moving_average:
          alpha: 0.09
          send_every: 1   

### Does voltage divider calculations to determine resistance of thermistor ###
  - platform: resistance
    id: resistance_sensor
    sensor: adc1
    configuration: DOWNSTREAM
    resistor: 10000Ohm
    filters:
### Custom filter to filter out obviously erraneous values ###    
      - lambda: |-
            if (400000 >= x && 200<=x) return x;
            else return {};  
### Median filter to minimize influence of outlier values ###
      - median:
            window_size: 30
            send_every: 1

### Reads voltage from External Analog to Digital Converter ###
  - platform: ads1115
    multiplexer: 'A0_GND'
    gain: 4.096
    id: adc1
### Might be able to read faster than this. Have not tried yet ###
    update_interval: 0.75s
### Been working on temp control and signal filtetring. Will implement meat probes to display in home assistant and on display ### 
  # - platform: ads1115
  #   multiplexer: 'A1_GND'
  #   gain: 4.096
  #   id: adc2
  # - platform: ads1115
  #   multiplexer: 'A2_GND'
  #   gain: 4.096
  #   id: adc3
  # - platform: ads1115
  #   multiplexer: 'A3_GND'
  #   gain: 4.096
  #   id: adc4
  
###------------------------------------------------------------------------------###
### Rotary Encoder - Some code to function as state machine - UNDER CONSTRUCTION ###   
###------------------------------------------------------------------------------###
  - platform: rotary_encoder
    id: rotary
    pin_a: GPIO23
    pin_b: GPIO22
    on_value:
      then:
        - if:
            condition:
              lambda: 'return id(edit)==false;'
            then:
              - if:
                  condition:
                    lambda: 'return id(rotary).state > 5;'
                  then:  
                    - sensor.rotary_encoder.set_value:
                        id: rotary
                        value: 1
              - if:
                  condition:
                    lambda: 'return id(rotary).state < 1;'
                  then:  
                    - sensor.rotary_encoder.set_value:
                        id: rotary
                        value: 5                  
              - display.page.show: !lambda |-
                  if (id(rotary).state==1) {
                    return id(page1);
                  } if (id(rotary).state==2) {
                    return id(page2);
                  } if (id(rotary).state==3) {
                    return id(page3);
                  } if (id(rotary).state==4) {
                    return id(page4);
                  } if (id(rotary).state==5) {
                    return id(page5);
                  }
              - globals.set:
                  id:  current_page
                  value: !lambda |-
                    return id(rotary).state;
            else:
              - if:
                  condition:
                    lambda: 'return id(rotary).state == 1;'
                  then: 




###-------------------------------------------------------------------###
###                           Display                                 ###
###-------------------------------------------------------------------###  
font:
  - file: "chary.ttf"
    id: font_14
    size: 14
  - file: "chary.ttf"
    id: font_12
    size: 12
image:
  - file: "grill.png"
    id: grill
    resize: 24x24
  - file: "meat.png"
    id: meat

    
display:
  - platform: ssd1306_i2c
    model: "SSD1306 128x64"
    id: oled
    brightness: 1
### Originally set this entirely too fast. Got fast reponse from rotary encoder but caused frequent api disconnects and reconnects ###
    update_interval: 0.5s
    address: 0x3C
    pages:
      - id: page1
        lambda: |-
          if(true){
          it.strftime(40, 0, id(font_14), "%I:%M%p", id(my_time).now());
          }
          it.print(5, 16, id(font_12), "Grill Temp");
          it.printf(10, 34, id(font_14), "%.1f F", id(temp1).state* (9.0/5.0) + 32.0);
          it.print(82, 16, id(font_12), "Mode");
          it.line(5, 28, 64, 28);
          it.line(80, 28, 105, 28);
      - id: page2
        lambda: |-
          it.print(0, 10, id(font_14), "This is page 2!");
      - id: page3
        lambda: |-
          it.print(0, 10, id(font_14), "This is page 3!");
      - id: page4
        lambda: |-
          it.print(0, 10, id(font_14), "This is page 4!");
      - id: page5
        lambda: |-
          it.print(0, 10, id(font_14), "This is page 5!");
      - id: page11
        lambda: |-
          it.printf(0, 10, id(font_14), "This is %4.0f!", id(current_page)+id(rotary).state);
          it.line(100, 10, 128, 10);
      - id: page12
        lambda: |-
          it.print(0, 10, id(font_14), "This is page 2!");
      - id: page13
        lambda: |-
          it.print(0, 10, id(font_14), "This is page 3!");
      - id: page14
        lambda: |-
          it.print(0, 10, id(font_14), "This is page 4!");
      - id: page15
        lambda: |-
          it.print(0, 10, id(font_14), "This is page 5!");
          

7 Likes

I’ve wanted to do something like this for a gas smoker but I haven’t found an electrically regulatable propane gas valve. Everything is either on/off or manual knob controlled.

I’ve already got the Nodemcu with two probes (one for meat and one for the smoker itself) that goes into HA so adding the reguator from HA to control the output might not be too hard.

If I could just find a valve…

What kind of output does the controller have? relay or analog?

What probes did you use for this? Any further info? :smiley: I am currently using a Bluetooth Thermometer with up to 6 probes that connects to my phone, but something I could build automations of would be great.

I am also using an electric smoker

https://www.amazon.com/Masterbuilt-MES-35B-Electric-Smoker/dp/B07NQLF9WD?ref_=ast_sto_dp

So I am following this somewhat carefully to see if I can modify it.

My project would be perfect for your smoker. As far as probes, I am using thermoworks pro series thermistor probes suggested for the heater meter project(charcoal smoker controller). Very high quality with a great price. I am using them with an ADS1115 since the ESP32 ADC is quite inaccurate. I may end up using a thermocouple for a little more stability on the temp control side. But I’m still experimenting with signal filtering. I’ll keep updating as I make more progress.

How many turns is the propane regulator? Maybe a servo could do the job! The output of the controller is slow PWM (2s period) through a solid state relay. So kinda almost maybe analog.

My project would be perfect for your smoker. As far as probes, I am using thermoworks pro series thermistor probes suggested for the heater meter project(charcoal smoker controller). Very high quality with a great price. I am using them with an ADS1115 since the ESP32 ADC is quite inaccurate. I may end up using a thermocouple for a little more stability on the temp control side. But currently I can use 4 probes total, 1 for the grill and 3 for meat.

I’ll keep updating as I make more progress with filtering the thermistor signal

Take a look at this https://www.smokingmeatforums.com/threads/added-valves-plus-pid-controller-to-propane-smoker.282441/

1 Like

Temp control is a big problem with this smoker. It swings wildly up and down as the element turns on and off. It has a dial to “control” the temp, but it is worthless.


So I have been thinking that I could use an automation with some sort of HA connected temp probe that could then turn on and off a smart plug into which the smoker is plugged and temp dial turned up all the way.

I think a smart switch would almost certainly fail from the frequent switching that would be required to get good control. I considered the smart plug route early on but quickly realized I would need a solid state relay and a PID controller.

My project would work how you explain. The controller plugs into the wall, and the smoker
and temp probes plug into the controller. The knob on the smoker would be set to max. But all automation is done outside of homeassistant with ESPhome on the controller itself. Home Assistant is only a way to change the operating modes/temperature. This also means that the controller doesn’t need to be connected to Home Assistant to work.

I’ll share pictures, schematics and more information when I get home. The project itself is quite easy. The only semi-complicated part that I have not yet completed is the OLED and rotary encoder menu system with settings.

1 Like

Awesome. I’m looking forward to it.

I have updated the original post with more pics, info and a schematic.

Looks great!! I’ll have to study that schematic more closely, but this appears to be a “little” above of my skill level. Lol

Its truly not all that bad. Give me a minute and I can make a simple schematic that will be easier to follow. I have just always like net labels instead of drawing wires.

I am actually starting to follow it now. Just needed to enlarge it take a closer look.

This is the thermometer I am currently using. The probes appear to use the some connector your probes use. Hopefully I will be able to reuse them if I can make this work.

https://www.amazon.com/gp/product/B084DJM66G/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&psc=1

Those probes may work. But if you have a multimeter you should check the continuity between the tip of the plug and the stainless braid and also between the ring of the plug and the stainless braid. Sometimes cheaper probes will use the stainless braid as one of the conductors for cost savings. This is not a good thing.

Looking at the schematic your output is just binary - either on or off? I was thinking about a PID for my (already completed) proofing box project, but was put off by this proviso in the ESPHome documentation:

  • Please note the output must be controllable with continuous value (not only ON/OFF, but any state in between for example 50% heating power).

My heating is done via a 500W ceramic fan heater.

I may have to do a PID version and see if the results are any better. This is a plot of my temperature vs time, the bump in the middle is where I increased the set temp by a degree or so.

I’ll check that out. A couple of things I am not sure about from the schematic. This is where the the AC comes in and passes through the relay on it’s way to the AC out. How exactly do these wire to the plugs.

image

And speaking of the plugs, how would the AC out be changed over to 3 prong grounded? I am passable when working with DC, but AC I usually leave alone unless it is just changing out a light switch or wall outlet.

image

The output is technically digital but implemented through slow PWM which is a form of Digital to Analog conversion, but it is not analog in the same way a dimmer would be. That uses zero-cross detection and phase chopping to modulate the power delivered.

Slow PWM is mentioned in the ESPHome PID climate page as a suitable output. It says TODO but I think that was just missed in the pull from beta to main because I am using slow PWM without problems.

Those rectangles that are labeled L, N, and Load are thru hole male blade terminals. The connections would then be made from board to receptacle with a piece of wire and a female blade terminal crimped on each end.

Obligatory “This is mains voltage which can kill you. Always work with power off and do not attempt unless you 100% know what you are doing. The mistakes that don’t end up killing you could potentially hurt or cause death to others.”

That said, if you have wired a light switch before just think of the SSR as the light switch.

Line(hot), neutral and ground would come from the wall and go in through the IEC socket. The line(hot) then goes out to the both the power supply and the solid state relay. The load side of the SSR would go to the Line(hot) side of the 3 prong receptacle that the smoker plugs into. Neutral goes to the the power supply and the neutral side of the 3 prong receptacle that the smoker plugs into. Then grounds are connected between IEC socket and the 3 prong receptacle and also connected to the chassis if it is made of metal.